


better remember lightning never strikes twice

by StopIWantToTalkAboutCheese



Series: lightning never strikes twice [1]
Category: Percy Jackson and the Olympians & Related Fandoms - All Media Types, Percy Jackson and the Olympians - Rick Riordan
Genre: Alternate Universe, BAMF Thalia Grace, Character Death, Crack Treated Seriously, I love time travel stories can you tell, I will add more tags as I go, POV Thalia Grace, Time Travel, also, either that or the oa, it has nothing do do with the fic i just think everyone should watch it, please, psa: watch dark on netflix i promise you won’t regret it, thalia grace-centric, this was partially inspired by back to the future part 2
Language: English
Status: Completed
Published: 2020-07-21
Updated: 2020-08-23
Packaged: 2021-03-04 21:48:56
Rating: General Audiences
Warnings: Creator Chose Not To Use Archive Warnings
Chapters: 7
Words: 12,887
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/25413457
Author URL: https://archiveofourown.org/users/StopIWantToTalkAboutCheese/pseuds/StopIWantToTalkAboutCheese
Summary: Thalia Grace, lying beneath the statue of Hera as her friends go to confront Kronos, has had enough. When an opportunity to travel through time comes up, she jumps at it. She’s going to get rid of Luke, before he even had a chance to hurt people. She’s going to fix everything.
Relationships: Annabeth Chase & Thalia Grace, Annabeth Chase & Thalia Grace & Grover Underwood, Luke Castellan & Annabeth Chase & Thalia Grace
Series: lightning never strikes twice [1]
Series URL: https://archiveofourown.org/series/2186229
Comments: 18
Kudos: 73





	1. The Opportunity

**Author's Note:**

> I have not read pjo in YEARS. Hopefully this doesn’t accidentally contradict canon lol.

**_August 17, 2009_ **

Thalia hated waiting.

She had once spent five years doing nothing _but_ waiting, and that was enough for her, thanks very much.

And yet, here she was. Pinned beneath a statue of Hera. Leg in agony. Waiting.

It wasn’t really the waiting itself that was so bad. Sometimes, waiting was fun, like when she was hiding in the woods, ready to trigger an ambush with her sisters of whatever monster they’d managed to corner that day. So it wasn’t really the waiting. It was the uncertainty, and right now, that uncertainty was made all the worse by the fear.

Kronos was here. _Luke_ was here. And Annabeth, Grover, and Percy were alone. 

Gods, why did she have to be trapped beneath this _stupid statue?_

This was just her luck. 

The bridge was still crumbling. Thalia tried not to look down.

_Gods, I hate heights._

And her leg was in _agony_. Gods, _why_ had she been so stupid as to forget nectar and ambrosia? She had thought she would be fighting! _Why had she forgotten the nectar and ambrosia?_

Well, no use kicking herself now. It wasn’t like she could anyway; the leg was definitely broken. All she could do was _wait._

Thalia groaned, and let her forehead thud down onto the cold tile.

“Hello, little sister.”

Thalia’s head shot up so fast she nearly gave herself whiplash. Her knife came up, and her free hand scrabbled for her bow, but it was too far away.

The person regarding her was handsome, a young man with a single lock of hair that spilled over his brow and nose. The rest of his head was bald, the style almost reminding Thalia of a monk. But the unfortunate haircut wasn’t what ruined his good looks. No, that dubious honor belonged to his eyes, the cold golden eyes that seemed to pin her to the spot. 

A sneer curled the young man’s lip, and a shiver ran down Thalia’s spine. She had no doubt– this man was a god, and not a particularly friendly one at that. She would have to be careful.

But who was he?

When Thalia was a kid, she had memorized the twelve main Greek gods, and a few minor ones, too. Once she was on the run with Luke and Annabeth, she had quickly learned more. When your life often depended on knowing who was who when it came to the gods, it was a handy skill to have.

But this man was completely unfamiliar.

“Who… are you?” Thalia croaked, struggling for breath. “Are… are you a… minor god? Are you here to… help us?” 

“My name is Kairos,” the god said, and for the first time, Thalia noticed that he was standing on tiptoe. Why, she had no idea. She was on the ground, it wasn't like she was taller than he was. “I am the god of opportunity.”

“Never… heard of you.”

Something in the god’s face tightened minutely. “I am not as well known as my Olympian brethren.”

“You a… minor god?” Thalia wasn’t sure why she asked. He obviously wasn’t one of the Twelve, and if Thalia had never heard of him, odds were he was _really_ minor. She lived with Annabeth for a good portion of her life. She knew the gods like the back of her hand.

Either way, Kairos didn’t seem bothered, if the calm look he gave her was any indication. “If that’s the way you want to put it.”

Something clicked in Thalia’s brain. 

“You… called me… _sister."_

“I, too, am a child of Zeus, Thalia Grace.”

“Don’t… call me… that,” Thalia managed. “I… hate that name. So… Kairos. Are you… here to help us?”

“That depends on you.”

Immediately, Thalia tensed up. That was never a good phrase. “What… do you mean?”

“I will give you three chances,” Kairos said. His face was unreadable.

“Three… chances for… what?”

“For you to seize an opportunity.” Kairos held up a hand, and a perfect black orb materialized in the center of it. “I am the god of fleeting moments, little sister. Once the opportunity is gone, it can never be recovered. However, just this once, I will make an exception. Once your opportunities are spent, you may not ask for more. I do not offer second chances.”

“What… opportunity?”

“Time travel.”

“...What?”

“I will give you three chances, little sister,” Kairos warned her. “Only three.”

“Wait… wait. Time travel? As in… _time travel?_ ” 

“You want to fix this mess, don’t you?” Kairos gestured around at Olympus as it crumbled. “You want to keep your friends safe, don’t you?” He pointed to the door. “They are in there, right now, facing Kronos without you. Don’t you want to be there, keeping them safe?”

Thalia bristled. “Of… course I do.” She had meant to say it indignantly, but it was getting harder and harder to focus. _Femur,_ she thought, remembering long afternoons surrounded by medical supplies with the other Hunters. _Femur’s definitely broken, fractured maybe. But probably broken._ “Why… should I… trust you?” she managed.

Kairos snapped his fingers, and the pain in her leg vanished. At her gasp of relief, his eyes flickered the tiniest amount. “A temporary fix, little sister, so be cautious. Tell the orb the exact date and time you want to go to. Three chances. Seize your opportunity. Good luck.”

He pressed the sphere into her hands and vanished.

Thalia’s mind whirled. Where to go first? Could she go back to when Percy had gone into the Labyrinth and everything changed? Could she save Zoë? Bianca? Jason?

Her baby brother, the reason she had finally run away, the final push that sent her down this path in the first place. Could she save him, and live a life far away from half-bloods and gods, with no monsters except the one who gave birth to them? Could she do it? Could she keep him safe? Her pride wanted her to say _yes,_ to go back and rip Jason out of her mother’s arms and never let him go. She could do it. It would be so easy.

But… but the throne room. Annabeth. Kronos. _Luke._

No.

Thalia loved her little brother. She always would. But one little boy, versus the rest of the world? 

Thalia was not that selfish.

She had to stop Luke first. 

And then… maybe, if there was time, if she saved her last chance… maybe then she could make sure her brother had the chance to grow up.

_Seize your opportunity._

She clutched the orb to her chest. It buzzed faintly at being clutched so tightly. 

Thalia closed her eyes and pictured a particular forest. 

“June fifth, 2000. Ten AM,” she whispered to the orb, and everything went black.

**Notes for the Chapter:**

> Hello there! Thank you for reading my fic!
> 
> In Greek mythology, Kairos is the god of opportunity, and is also called Caerus. Although he isn’t a god that deals in time or time travel, I thought he would fit the bill for ‘shady yet dependable minor god who can get this plot moving’. Keep an eye on him, he's coming back.
> 
> The title for this fic came from the song “Back In Time” by Huey Lewis and the News. I wanted to pay homage to "Back to the Future", and even though I love “The Power of Love”, it isn’t exactly a song I would associate with Thalia. Also, I couldn’t resist the double pun.


	2. The First Chance, Part I

_**June 5, 2000** _

Thalia jerked awake, breathing hard, in a green, rustling forest in the middle of nowhere and with Luke, Annabeth, and Grover nowhere to be seen.

_Great._

Thalia was not surprised that they weren’t in her immediate vicinity, but she _was_ annoyed.

The date had been more or less completely arbitrary. The summer of 2000 was important, as it was the last few weeks she, Annabeth, Grover, and Luke had been wandering the East Coast, but she hadn’t known exactly where they had been located at any given time. She didn’t remember June being particularly important, but she had been turned into a tree by early August. An assassination in the middle of Camp Half-Blood probably wouldn’t go over too well, but if she caught Luke unawares in the woods, well… he was a fourteen year old with a golf club and she was a highly trained Hunter of Artemis. There would be no contest.

Two months should give her plenty of time to figure out what, exactly, she planned on doing. Obviously she had to get rid of Luke somehow. But how?

A lightning strike was too obvious, and overkill besides. She couldn’t sneak up behind him, Luke was always good at knowing when he was about to be ambushed. It was too bad she hadn’t thought to go farther back… but no. Fourteen year old Luke looked close enough to twenty-two year old Luke that she could do it, but a baby… Thalia shuddered.

Wait. _June_. There _was_ something important about that month, something she had overlooked but was still important. Thalia grinned to herself.

 _The Hunters._ This was when they had met the Hunters.

Surely Zoë Nightshade, of all people, could be convinced to get rid of Luke. Even though Zoë wasn’t a murderer, she still hated boys, and at this point in time, Zoë was, crucially, still alive. She could distract Annabeth and Thalia’s younger self, keep them occupied while Thalia took Luke to a secluded area, armed with a knife and a bow while Luke had nothing… 

Thalia shuddered, suddenly feeling nauseous. The weight of what she was planning seemed to hit her full-force. To kill in the heat of battle was one thing. To kill an unarmed boy… 

No. She had to focus.

Thalia would have to get Luke alone, first and foremost, so that the others didn’t fight back. She would also have to keep him alive long enough to make sure Annabeth and Thalia’s younger self survived the journey to Camp Half-Blood. As much as she hated to admit it, he had been indispensable during their travels. If she killed him discreetly enough, Thalia herself might be able to take his place as co-protector of the group, but two children of Zeus might be tempting enough that her mere presence would get everyone else killed a lot faster. And getting Annabeth killed was definitely out. 

…Wait.

What was that noise?

It sounded like people talking. Loudly.

Actually, one of those voices… had a _familiar_ lilt to it.

“–lost in the woods somewhere in New Jersey and we’re never gonna make it to camp!”

Yeah, Thalia would recognize that high-pitched panic _anywhere._

 _Grover_.

Before Thalia could debate with herself about whether or not she actually wanted to reveal herself versus secretly offing Luke in the middle of the night, they were practically on top of her.

Thalia saw Annabeth before Annabeth saw her.

The tiny blonde was stumbling along, looking dead on her feet. There was a long gash across her face, probably from an attack that Thalia couldn’t remember. Her big gray eyes were sunken and tired, but were darting around, perpetually on alert. She froze when she saw Thalia.

Before Thalia could manage some kind of reassurance other than reflexively lifting her hands, Annabeth had stumbled back with a shriek.

“Annabeth!” Thalia heard Luke yell, and then there was the crashing sounds of three kids, all running through the undergrowth, coming straight towards Thalia.

“It’s okay!” Thalia tried to say, but she didn’t get much farther than that as Luke leapt out of the surrounding forest with a yell, bringing down his golf club simultaneously. Thalia rolled, narrowly avoiding it as it bashed into the ground next to her.

Drawing her knife, she jumped to her feet and whirled, only to come face-to-face with Aegis. She staggered backwards, horrified, and barely had the presence of mind to slash at Luke as he tried to come in for another attack.

“Go away, monster!” Annabeth yelled, and Thalia dodged as a knife came spinning through the air, only to bounce off a tree and fall uselessly to the ground.

“Wait!” she shouted, and cursed, flipping her knife to the other hand. “I don’t want to fight!” At that moment, she spotted Grover, hovering at the edge of the fight, eyes wide and terrified, and dove straight towards him, grabbing his arm and using her momentum to slam them both to the ground. Rolling to a crouch, Thalia pointed her knife at his throat. “Freeze! Everybody freeze!”

Annabeth screamed. Luke went still.

And Thalia looked around the destroyed clearing.

There was Annabeth, pale and trembling. Luke, annoyed and scowling. Grover, whimpering in her arms.

And there she was.

Her younger self.

For a split second, Thalia forgot everything: the mission to kill Luke, her plan, Jason, all of it. She couldn’t help but stare.

Her hair was longer back then, and tangled, and she was a lot thinner. They were all a lot thinner. She was wearing grimy clothing, and just like Annabeth, there were dark circles beneath her eyes.

She looked like a wild animal. Annabeth and Luke, too.

“If I let him go,” Thalia said through gritted teeth, “do you swear on the Styx not to attack?”

Luke and her younger self went stiff, and shared a look. Thalia waited.

“Shapeshifter,” her younger self said grimly. “What monster can shapeshift?”

“I don’t _know_ ,” Luke hissed. “Annabeth?”

“I don’t know,” Annabeth whispered, staring at Thalia and Grover in transfixed horror.

_Great. I’ve managed to traumatize an eight year old. How wonderful._

“You didn’t do a very good job,” the younger Thalia snapped, glaring at her. “I look nothing like you.”

Despite herself, Thalia cracked a smile. “Is that what you think? When was the last time you were within fifty feet of a mirror, kid?”

“Wait,” Luke said, and his voice was choked. “Look.”

He pointed to Thalia’s arm. Automatically, she looked down, and flinched. What a way to let down her guard.

But they weren’t attacking. 

Gradually, Thalia became aware of a stinging on her forearm, and looked down, deliberately this time.

She had hurt her arm at some point in the scuffle, and the scrape was welling up with dark red blood. Human blood. So that’s what they were looking at.

Slowly, Thalia put down her knife, but kept her hold on the collar of Grover’s shirt. “Do you know who I am?”

“Thalia,” Annabeth whispered. “You’re Thalia.”

“That’s impossible,” her younger self (and gods, that was going to get old fast, wasn’t it?) snapped, but her eyes were locked on Thalia’s face. “...Right?”

“Come on,” Thalia said. “At this point, haven’t you seen weirder things than time travel?”

“Not really,” her younger self deadpanned, but slowly put down her spear. Luke followed suit with his golf club, and Thalia shoved Grover towards them, letting his shirt go.

“There’s only one person who can control time,” Luke said. “Kronos. That Titan who ate his kids. Did he send you here?”

Thalia wanted to laugh at the irony. “No,” she said. “Kronos actually had nothing to do with it.”

“How old are you?” Her younger self demanded.

“Sixteen,” she answered, and Grover’s eyes got huge.

Whoops. She should have said fifteen. Well, too late now.

“So you’re from a couple years in the future,” Luke said, oblivious to Grover’s shock. “Why are you here now?”

“Um,” Thalia said. How had she not thought of a cover story? “It. Was. Um. An… accident?”

Her younger self didn’t look convinced, but Luke laughed.

“It’s just like you to accidentally get thrown two years back in time,” he said. 

“Did we make it to camp?” Annabeth asked, seeming to take Luke’s laughter as a signal to relax. She was watching Thalia with bright, eager eyes, her exhaustion forgotten, and she said _camp_ like it was Eden.

“I… yeah. Yeah, you did.”

Annabeth whooped, and even Thalia’s younger self cracked a smile at that.

“We’d better make camp,” Luke said, glancing up at the sky. “I think we’ve gone far enough today.”  


* * *

Thalia knew that she should keep her guard up.

But gods, this was so _familiar_.

She had been traveling with the group for nearly three days, now. And she had slipped back into old patterns with a terrifying ease. Luke and both Thalias perpetually on guard. Grover and Annabeth helping each other along. Feeling like prey every time they felt safe enough to slow down. No monsters had approached them yet– perhaps they were confused by or afraid of the smell of two identical children of Zeus.

Luke was building a fire. Her younger self was sitting on a log, sharpening her spear. Grover was playing his panpipes, stealing nervous glances at the trees around them every so often. Annabeth was asleep, her head on Thalia’s lap.

But even as she hunted for food for the group, even as she told Annabeth about the future (carefully editing them so that Annabeth was only nine or ten in her stories), even as she told Grover about the boy named Percy Jackson that he would one day meet, she couldn’t let herself forget about the mission. She was here to kill Luke, not reminisce about old times.

“So… why are you wearing a crown?”

Luke’s question shook Thalia out of her thoughts. She turned to look at him in the dim firelight.

“It’s not a crown,” she said, touching the silver circlet on her head. Before she could elaborate, Grover broke in.

“That’s the mark of the lieutenant to Artemis,” he said. “You’re a Hunter.”

“Yeah.”

Grover frowned. “Hold on. Are you really sixteen?”

Thalia snorted. “Physically or mentally?”

“Both.” Thalia’s younger self moved into the circle of firelight, eyes fixed on the circlet.

“I might have fudged the numbers a bit. I’ve been a Hunter for about two years, now.”

“Whassa Hunter?” Annabeth asked sleepily.

“Are you _physically_ sixteen?” Grover pressed.

“Almost. I was about a day from my birthday when I took the oath.” Thalia met Grover’s gaze. “I’m not the child of the prophecy, Grover.”

“What prophecy?” her younger self said warily.

“A half blood of the eldest gods, blah, blah, blah, who cares you’re not in the prophecy anyway.” Thalia said dismissively.

“So who is?” her younger self said challengingly. “Is there another child of the Big Three out there? Is Ja–” she cut herself off.

“Not as far as I know,” Thalia said, as gently as she could, ignoring the stares from the others. “There’s another. A son of Poseidon. And…” she hesitated a moment, but decided it couldn’t do much harm, “two children of Hades. A boy, and… and a girl.”

Thalia could tell they were about to explode with questions, but the sound of a horn suddenly cut through the soft rustling of the woods.

Her younger self and Luke shot to their feet as one, pressing their backs against each other and circling warily. Grover grabbed Annabeth’s hand and dragged her to her feet as well. But Thalia herself stayed still. She knew that call.

The Hunters of Artemis were here.

**Notes for the Chapter:**

> kudos to you if you spot the tlt musical reference
> 
> (By the way, if this fic premise looks familiar… it’s because fellow AO3 author melimarron and I are friends, and we came up with this concept together. Go read their version! It's called "Thalia Grace’s Foolproof Guide To Punching Luke Castellan In The Face", and it's much crackier than I could ever hope to be. (warning: there will be spoilers for how mine is going to turn out))


	3. The First Chance, Part II

**Summary for the Chapter:**

> Thalia talks to the Hunters, and her friends start to get suspicious.

**Notes for the Chapter:**

> Fun fact: this chapter ALONE more than doubles the word count for this fic.
> 
> Also, I was taking complete shots in the dark on the placement of "thee", "thou", "thy", etc. so please tell me if I screwed that up and I will do my best to fix it!
> 
> Enjoy :)

“So,” Zoë Nightshade said, “thou are here from the future, sent here by the god Kairos, and thee wants to kill thy friend Luke Castellan, before he has the chance to become the host of Kronos. Am I correct?”

They were standing apart from the rest of the group, speaking in hushed tones. Artemis wasn’t there, which was good because Thalia did not feel up to explaining herself to a goddess.

“It’s not like I _want_ to,” Thalia said. “I _have_ to. So that everyone else… so that Annabeth and Grover… Percy, Artemis, all of them. I can stop Kronos. He can’t rise if he doesn’t have a willing host. So I just have to kill Luke. And I might need your help. So… will you?”

“Hm.” Zoë traced an infinity symbol in the dirt with her finger. She didn’t look at Thalia. “No.”

Thalia felt her heart stutter in her chest. “ _No?_ ”

“No.”

“But–”

Zoë stood. “I appreciate thine dedication to stopping my uncle,” she said. “And I would help, if thou were not from the future.”

“What do you mean?”

“Meddling in time is dangerous, Thalia Grace,” Zoë said, ignoring the way Thalia bristled. “I will not stand in your way, but I also refuse to be an accessory to whatever madness that may come of this. I am sorry.”

Zoë turned, and rejoined the group standing around the flickering fire. Thalia stared after her.

It wasn’t supposed to go like this.

She needed a new plan.

They were hours away from Camp, especially if they ran.

It was back to Plan A, she supposed, but the longer she spent with Luke and his non-corrupted, non-evil _fourteen year old self_ , the less sure she was about her plan to drag him into the woods and murder him.

Reluctantly, she made her way back to the campfire and sat down.

It was weird, seeing the Hunters. 

They all looked exactly the same, but they seemed to be a little more carefree. They weren’t tracking down monsters in the middle of a war. They hadn’t lost their lieutenant of a thousand years. Their goddess hadn’t been kidnapped and forced to hold up the sky. They still had faith that Zoë and Artemis, and by extension the gods, were infallible.  
But in sharing a single glance with her younger self, Thalia knew that they both knew better.

Thalia had taken off her Lieutenant circlet, mostly so they wouldn’t panic, but she still had her silver jacket and bow slung across her shoulders, and when Phoebe had seen her, she had smiled and called her _sister_. Her younger self had rolled her eyes at that.

For a few minutes, they all ate in relative silence. 

But then Zoë twitched her hand, a motion that was barely visible, and immediately, the Hunters began to pack up. Luke and the others went stiff.

“We will leave thee on thine own now,” Zoë said to Thalia. “We are tracking a monster at the moment– we cannot waste time escorting four half-bloods and a satyr to Long Island. However, if thine group goes about ten miles east, thee will be in the city. From there, thou can catch a bus–”

“Hey, wait a minute!” Thalia’s younger self burst out. “You can’t just– leave! We’re trying to get to Camp Half-Blood. You have to help us.”

Zoë gave her an appraising look.

“Thou could join us,” she said. “Annabeth is young, but we could take her, as well.”

“But you won’t take Luke,” Thalia said, and Zoë shot her a sharp look. “Sorry. But you should go, um, Thalia,” she said, stumbling over her own name. “You’ll be safer.”

“I’ll never join you!” Thalia’s younger self snapped, shooting a glare at both Zoë and Thalia. “Who would want to join a group that won’t protect someone just because he’s a guy?”

“He’ll be safer without you,” Thalia said quietly, and her younger self froze. “You’re a child of Zeus. He’s a child of Hermes. Monsters don’t care about him. The gods aren’t chasing him down like a dog. With the Hunters, you’d be under Artemis’ protection. You and Annabeth.”

“Are you trying to tell me something?” Thalia’s younger self asked, her face bone-white. “Does… does Luke die before we get to Camp? Is it my fault?”

Well, THAT wasn’t the message she had been trying to impart.

“I… no,” she said. “Not in my time. But, you know, two children of Zeus… we probably smell really, really good. Might make more sense to split up.” _Plus, that way, I’d have a better chance of… getting Luke alone._ She shivered, just a little.

“Yeah, you two smell like really good pizza,” Grover volunteered. “Or enchiladas.”

“Yes,” Zoë agreed. “Enchiladas.”

“I don’t think I’ve ever been compared to a pizza before,” Thalia mused.

“Enough!” Thalia’s younger self snapped, making them all jump. “We’re not leaving Luke or Grover behind. We stick together. End of story.”

Zoë nodded. “Then I wish you all luck.” With that, Zoë Nightshade picked up her bow and turned, vanishing into the shadows of the woods.

“We don’t need her,” Thalia’s younger self snarled. 

“Uh,” Grover said, “she _is_ a thousand-year-old Hunter of Artemis. And we are a bunch of teenagers and a literal child. We are children, and we need her.”

Thalia’s younger self rounded on him. “You told me you were twenty-one! That’s an adult!”

“Ask any twenty-one year old if they think they are an adult. I dare you.”

“Ugh!” Thalia’s younger self threw her hands in the air. Before she could continue arguing, however, a howl cut through the night.

Luke cursed, and shot to his feet. Annabeth was already standing, knife at the ready, gray eyes intensely focused on the woods around them. Thalia motioned for silence and listened carefully. 

Two big animals. One humanoid. Uneven footsteps. Heavy panting.

Thalia swore. “Two hellhounds and an empousa.”

Luke looked grim. “Run?”

Thalia eyed the shadows around them. “They’re too close. And they know we’re here.”

It was Luke’s turn to curse.

The five of them huddled in the center of the clearing, weapons ready and breathing shaky. 

“How did the Hunters disappear so fast?” Thalia’s younger self hissed. “You’d think they’d come help us!”

“They might be too far to hear the howling,” Thalia reasoned, and her younger self snorted derisively. "What? They probably waited specifically for the Hunters to leave!"

Thalia’s younger self’s lip curled. “This–”

The first hellhound attacked. 

Luke swung his club, and knocked the hellhound to the side. Thalia’s younger self charged after it as Luke spun to face the empousa. Thalia lunged with her spear as Annabeth and Grover let out simultaneous high-pitched war cries and started on the empousa.

The second hellhound snarled at Thalia, and Thalia aimed her spear at it. If the stupid dog wasn’t so close, she might be able to use her bow.

She tried getting a better grip on her spear and wished she’d had the foresight to take out her knife as the hellhound started swiping at her, snarling. Drool hung from its mouth, and it’s hate-filled eyes gleamed.

_Screw it_ , Thalia thought, and with a shout, called down lightning. It arced down and hit the hellhound squarely in the chest.

The hellhound exploded into gray powder.

Thalia spat dust out of her mouth and looked around for Annabeth, finally spotting her at the other side of the clearing. She was currently swinging her knife at the empousa, who was beginning to look like she would just jump on Annabeth, knife or no knife. Thalia called lightning to her spear and leaped forwards, stabbing it in the chest. The empousa got one last shrieking hiss in before exploding into dust.

“Aargh!”

The sudden cry had Thalia spinning around. Her younger self was clutching at her thigh, which was now gushing blood. The last hellhound melted into the shadows, but not before Luke got in one last good whack with his golf club.

Thalia mentally ran though every swear word she knew, including the ones in Ancient Greek she had learned from Zoë on their quest. “Hang on!”

Her younger self was breathing hard, clutching the injured thigh. Thalia absentmindedly ran her hand over the scar on her own leg, and felt her other, temporarily-healed, leg twinge in sympathy.

“What do we do what do we do _what do we do_?” Grover was babbling, eyes huge. He pressed his hands down on the wound, his breath coming almost as quickly as Thalia’s younger self’s was. “We’re out of nectar and ambrosia!”

“It looks like it missed the vital veins. Does anybody have a clean shirt?” Luke demanded, and Annabeth dove for her backpack and started digging through it. Luke’s gaze snapped to Thalia. “What did we do last time?” His tone brokered no argument.

“Last time, we went to May Castellan’s house,” Thalia admitted, not looking at Luke, who sucked in a harsh breath, “but we were in a different area, then. Closer to her. And it was weeks after we met the Hunters. They’re closing in on us, faster this time.”

“What did you change?” Thalia’s younger self demanded, wincing in pain. Electricity crackled in the air around them. “Gods, why are you even _here_? You never told us that.”

Thalia swallowed. “I came here by accident.”

“Bull. You–”

“Hey, hey!” Grover said, getting in between them. “Let’s not fight! The last thing we need is fighting!”

Thalia’s younger self threw her hands in the air, flinging blood all over the others. “Riddle me this: if you’re so concerned with us being tracked down by monsters, why did you meet up with us? Why are you still here? You’re right, two children of Zeus smell twice as good to monsters. Why not head south, or west, or north, or _away from us_ if you’re so desperate to keep us all safe? Why don’t you use your oh-so-amazing _Hunting_ abilities to confuse the monsters so there’s less of them to fight? I mean, according to you, we all survived the first time just fine on our own. Why not give us a little help?”

“I can’t tell you,” Thalia said through gritted teeth. “I’m just trying to get to camp.”

“Okay, that’s it.” Thalia’s younger self stabbed a finger at Thalia’s chest. “You’re a Hunter. You’re the goddamn _Lieutenant_. You came here, and you’ve traveled with us, but we have no idea where you came from, or when. You said there were two children of Hades out there, and a son of Poseidon. Why aren’t any of the monsters after them, then? Why are you here?”

Thalia took a deep breath and hoped she wasn’t screwing something else up. “The son of Poseidon’s scent is masked. He won’t be discovered for five more years. The children of Hades are protected right now, and neither of them will know who they are for _seven more years_. You and I are the only children of the Big Three running around the States. That’s why.”

“Seven?” Luke’s voice was quiet, and it took Thalia a moment to realize he had spoken. He was looking at her with an expression of mingled bafflement and hurt. “You said you were only from four years in the future. Two years as a regular demigod, and two years as a Hunter.”

“I said _about_ two years,” Thalia said quickly. “I was a little vague, sue me.” 

“That’s the second time you’ve lied to us about your age,” Luke said. A resolute expression spread over his face. “You’re up to something.”

“I–” Thalia spluttered. “ _What?_ ”

“He’s right,” Thalia’s younger self spit. “You’ve told us next to nothing, and what you _have_ told us have been lies. There’s no way you’re here by accident. You were way too calm for that. You captured Grover. You were going to hurt him. Why. Are. You. Here?”

“I wasn’t going to hurt Grover,” Thalia said, irritated. “I just wanted you guys to put down your weapons and see my face.”

“Well, couldn’t you have found a better way to get our attention than _attacking?_ ”

“You and Luke attacked first!” 

“Yeah! Because _we’ve_ been wandering around the woods being hunted by monsters for the better part of five years! We had no idea who you were, and you had Annabeth! There was no reason _not_ to attack!” 

“Look,” Thalia snarled, struggling not to let electricity crackle around her, “I have had a very long week. I’m here in service of the gods, okay? I can’t tell you what I’m here to do.”

“Because we’d stop you?” Thalia’s younger self challenged.

_Yeah, plus you aren’t going to believe me when I tell you your best friend is a monster._

Thalia just glowered at her, and her younger self nodded grimly.

“In that case, I don’t see any reason to keep on trusting you.”

Thalia wanted to scream. “I’m _you!_ ”

Thalia’s younger self shrugged.

“ _Seriously?_ ”

Luke put his hand on her younger self’s shoulder. His blue eyes were mistrustful.

“I think you’d better get out of here,” he said.

Slowly, Thalia packed up and headed into the trees, silently cursing both of her selves all the while.

She had allowed herself to get too comfortable.

Thalia had missed her chance.

* * *

The next two months were rough for the group. Having opted to follow along undetected, Thalia was busy tailing them, and thus couldn’t help when monsters attacked. That didn’t mean she couldn’t pick off the stragglers, but it was weird, especially as the group got closer and closer to camp. Her younger self’s leg began to stink and leak pus. Thalia watched in a tree as she winced and struggled to walk, perpetually on high alert for monsters, remembering those terrible final hours.

Today was the day. The day that Thalia had had nightmares about for years. Only in her dreams, it was always Annabeth or Grover who fell, and neither of them had a god powerful enough to save them. For a while, Luke had been a victim in those dreams, as well, but after their fight in California, he had started being the one to shove Annabeth and Grover into the salivating jaws of a hellhound.

As the group began to wake up and move east, Thalia followed silently, a shadow among the trees.

When this day had happened, the first time around, Thalia’s leg had been injured, yes, but it had had a couple of days to heal, albeit incredibly stressful ones. None of them had slept for those last few awful days. In the end, it had been the leg that had slowed her down just enough to know that she wasn’t going to make it, and she would rather die fighting than running.

And make no mistake, the group was running. Hellhounds snapped at their heels. Furies shrieked and tried to dive-bomb them, only for Thalia’s younger self to call down lightning and buy them a few more seconds as the Furies wailed. Luke was bashing in heads with his golf club, and Annabeth was slashing out with her knife. Both were caked in monster dust. Grover was tossing tin cans back at the horde, but was mostly leading the way, shouting “This way! This way!”

And then they got to Camp.

Thalia was frozen behind a tree, and gods, this was just like her nightmares. Her younger self was ahead of her, dragging her injured leg. Grover was sprinting at the front of their group, clutching Annabeth’s hand. As Thalia watched, Grover swung Annabeth up on his back and started going even faster.

“Thalia!” Suddenly, Luke had appeared at her younger self’s side. “Thalia, come on!” He offered his shoulder, and she wound an arm around it. Together, they struggled towards the Hill. 

They were going to make it.

And that could not be allowed to happen.

Thalia’s thoughts sped up and slowed down all at once.

If Luke made it to Camp, she would never have another chance to kill him. Leaving him alive introduced too many variables. Annabeth was safe. Grover was safe. Her goal had been halfway achieved.

Kronos could not be allowed to rise. Kronos could not be allowed to put everyone she loved in danger. She had to remember that, or everything would be for nothing.

To completely achieve that victory, Luke had to die. 

It was like she was having an out-of-body experience, watching a different person as she loaded her bow and aimed. Luke and her younger self were almost at the base of the hill. Grover was nearly at the Big House. Subtlety was out. But nobody was looking at her. The only people outside were Chiron, Grover, Annabeth, and her younger self.

And without Luke, her younger self would surely fall. It was unfortunate– she had hoped to avoid becoming a tree again– but there was no other choice. There could be no witnesses to what she was about to do.

_A single choice shall end his days._

Thalia fired exactly once.

A Hunter of Artemis never misses.

Luke went down, a silver arrow tip sticking out of his forehead.

There was a horrible, gut-wrenching _scream_ , and Thalia watched, dazed, as her younger self went down with Luke, covered in his blood, screaming.  
It didn’t take long for a hellhound to leap onto them.

Thalia watched in a daze as her own body was torn to pieces. She watched as a young, strong pine tree erupted from the bloody mess, and branches spread out over the body of a blond teenager who would never grow up to do terrible things.

Without Luke, the tree would never be poisoned and Thalia’s younger self might spend the rest of her life trapped in amber– frozen, but unaware. 

It was better this way.

It was better this way.

It was better this way.

Thalia could hear Annabeth screaming bloody murder. She could hear Chiron shouting to prepare two shrouds. She could hear Grover trying to wake Luke up.

She looked down. In her shaking hands was the pulsating black orb. She didn’t even bother to question where it had come from.

Forget her mission to find Jason. She needed to go back. She needed to see what she had achieved. She needed to know that it had been worth it.

“August 17, 2009,” she said softly, picturing Half-Blood Hill, pristine and not covered in the blood of dead demigods, and everything around her vanished.

**Notes for the Chapter:**

> lol this was supposed to be a crackfic but i don't think i achieved that


	4. The Second Chance

**Summary for the Chapter:**

> Thalia arrives back in 2009, and everything has gone spectacularly wrong.

**Notes for the Chapter:**

> What's this? Two chapters in one week?  
> Please don't get used to this, haha.

**_August 17, 2009 (Alt.)_ **

Thalia opened her eyes to see four blades positioned directly over her throat.

_Uh oh_.

“Thalia Grace,” the lead camper, a girl Thalia didn’t recognize, said grimly. “You’re coming with us.”

“...What?” Thalia said belatedly. The four campers exchanged a glance, and one lifted the butt of his sword. There was a dull pain in Thalia’s left temple, and everything went black.

* * *

Thalia woke up a few minutes later in the camp hospital to see Annabeth Chase, all of sixteen years old, standing ominously over her.

“Annabeth–” she began, but Annabeth cut her off, gray eyes hard.

“Who are you?” Annabeth demanded. The ice in her voice took Thalia by surprise. So did the knife clenched tightly in her hand. Luke’s knife. Thalia took a deep breath.

“I’m Thalia,” she said. “I time-traveled to about nine years ago from the future– now– by acci–”

“No way,” Annabeth said. “That worked when I was seven. You’re a time traveler, fine. But there’s no way you’re from _this_ time period. And there’s no way Luke’s death was accidental. We saw the arrow.”

Thalia swallowed. “I can explain.”

Annabeth leveled her knife directly at Thalia’s face. “Explain fast, then. Because you either came from _this_ timeline, or a totally different one. And judging by the color of your eyes, it’s definitely the second one.”

“The color of my– what?”

“They’re blue, not gold,” Annabeth said grimly, “which means you’re a different Thalia Grace. Ours is the servant of the Titan Kronos.”

* * *

_I screwed up I screwed up I screwed up_.

Thalia had never in her life screwed up quite so badly as she had now. Here she was, lying in a hospital bed, being glared at by Annabeth Chase, and she had apparently screwed up the timeline badly enough that not only were her friends in danger _anyway,_ apparently _she_ had been the one to put them there.

“I can explain,” she said again, helplessly. “I– I swear to you, I swear on the River Styx, I’m on your side.”

Above them, thunder rumbled. Annabeth relaxed minutely.

“Okay,” she said. “I’m not saying I trust you yet, but… tell me everything. No lies. No omissions. _Everything._ ”

“Deal.” Thalia said.

* * *

It took several hours to tell Annabeth everything that happened to her since she’d been tree-ified. She even threw in tidbits about what happened to Percy. He was the child of the Prophecy, after all, and not including him would probably count as omission.

As she spoke, Thalia slowly started to sit up, and Annabeth didn’t stop her. When she got to Percy’s first quest, Annabeth interrupted for the first time, eyes sharp and interested the same way they had been when she was seven years old and Thalia was dramatically retelling _Star Wars_ for the eighth time around the fire (Annabeth had always tried to argue that lightsabers were weapons that were physically impossible to wield).

“Somebody stole Zeus’s lightning?” she said, astonished. “Who would be crazy enough to– never mind, keep going.”

Thalia did, but Annabeth would latch onto seemingly innocuous parts of her story to try to pick them apart.

“What did you do after waking up from being a tree?”

“What did you think of Nico and Bianca?”

“So you threw Luke off a cliff?” 

“Is Atlas still holding the sky in your world?”

“You said Percy found Luke in the coffin? Where in the Labyrinth was this?”

And finally, “So who, exactly, is the prophecy child?”

“Percy,” Thalia answered, bemused. “I mean, I’m a Hunter, and he’s the next-oldest Big Three kid, so…”

Annabeth nodded, but she seemed distracted. “And Luke is Kronos’s vessel, not you.”

“Yeah.”

Annabeth nodded again. “So why _did_ you decide to time travel?”

Thalia looked at the ground. “I didn’t think,” she admitted. “I thought, by killing Luke, I was getting rid of the only viable host for Kronos. I was arrogant and stupid. I guess I underestimated my own resentment of the gods.”

To her surprise, Annabeth snorted derisively. “The gods. They’ve never done anything for us, have they?”

“I…” Thalia faltered. “I guess not, not in your world, but–”

“You’re a Hunter. So you have to be loyal to Artemis. I get that. But come on, Thalia. Zeus left you with your mom, who was so horrible you ran away. Athena left me with my dad, and the same thing happened. Luke’s mother was crazy, but did Hermes care that he was leaving a young child in that place? Nope. And Poseidon did the exact same thing with Percy and his stepfather. And now we’re here, fighting their war, and we’re dying, and what are the gods doing? They’re hiding. They’re cowards. I don’t agree with Kronos, but I’m only choosing the gods because I’d rather side with the evil I know.”

Thalia swallowed. She wasn’t going to pretend she hadn’t had similar thoughts in the past. No demigod was without resentment. 

“What happened here?” she asked softly.

“A lot of similar things to your timeline,” Annabeth said slowly. “Somebody poisoned Thalia’s tree, so we sent a quest to find the Golden Fleece to heal her. Percy, Clarisse, Grover, and I ended up retrieving it. Oh, and a Cyclops named Tyson.”

“I know him,” Thalia said distractedly. “Percy’s little brother. What happened next?”

Annabeth swallowed. “Thalia was healed, and she… came out of the tree. But she was– different. She said she’d been having dreams, while she was in the tree. She saw Luke, with golden eyes.”

Thalia nodded. “Kronos.”

Annabeth, looking somehow nauseated and grim at the same time, nodded back. “Two days after she woke up, Thalia was gone.”

“ _What?_ ” Thalia blurted out. “But camp-” Camp Half-Blood wasn’t perfect, but she had been trying to reach it for _years_. Camp was heaven, the Promised Land, the only safe place in the entire world. And she had been so desperate to be safe. Why had she left? Suddenly something else occurred to her. “Hold on. Luke’s dead in this timeline, and– uh– _your Thalia_ couldn't have possibly poisoned _herself_. Who…?”

Annabeth sighed. “Silena Beauregard, we think,” she said. “She’s still under investigation.”

Thalia sat back in her chair, feeling sick. She had only wanted to help. And she had only made everything worse. “Silena’s a hero,” she said quietly. “Where I come from, she was one of Kronos’s agents, but she died a hero.”

“Not in this world,” Annabeth said, a little coolly.

_Fair enough._

Annabeth kept going. The mission to recruit Bianca and Nico DiAngelo went more or less the same as before. Annabeth had been kidnapped, but the DiAngelos arrived safely at Camp. Zoë Nightshade, the Hunters, Grover, and Percy Jackson were with them, as were Artemis and Apollo. Percy was (reluctantly) allowed on the quest in Thalia’s stead. According to Annabeth, who had apparently heard the entire thing from Grover, he and Zoë had fought the entire time. Meanwhile, Grover and Bianca bonded over sharing annoyed and helpless looks with one another.

Bianca died in the land without rain, and Grover left with Bessie. Zoë and Percy were alone when they went to face Atlas.

At this point in Annabeth’s story, Thalia felt a sinking sensation in her gut. Grover had been the one to tell Annabeth all of this. The half-bloods were floundering, and more and more were deserting their cause every day. Percy was nowhere to be seen.

_No. Oh, no._

Annabeth went on, shakily.

“They got to Mount Tam,” she said, “and Zoë was all scratched up. I don’t know what happened to her. Thalia was there. Lady Artemis was holding the sky. Thalia and Percy and Zoë started to fight. But then Atlas showed up, and Percy… Percy…” there were tears building in Annabeth’s gray eyes. “He tried to take the sky,” she whispered, “but Atlas was too quick. He… he knew Artemis could win in a fight. He couldn’t let her be freed. And Zoë was busy with Thalia. He had my knife, and he…”

“Oh, gods,” Thalia whispered. 

Annabeth brushed away her tears. “My… my dad showed up, with his celestial bronze bullets. He saved me, but he couldn’t save Percy or Zoë. We had to leave Lady Artemis there.” 

In the end, Thalia’s other self had retreated, triumphant, with Atlas in tow. The next day, she turned sixteen, and the prophecy began.

Thalia felt sick.

“ _A half-blood of the eldest gods shall reach sixteen against the odds_ ”, Annabeth quoted. Her lips quirked upwards in a mirthless smile. “Thalia was trapped in a tree for six years. If that isn’t “against the odds”, then what is? And she was hours from turning sixteen when she freed Atlas and swore herself to Kronos.” She hesitated a moment. “We’re not sure about the _endless sleep_ line yet, but–”

“I do,” Thalia said, remembering the eerie stillness of Manhattan. “Keep going, I’ll fill you in in a minute.”

“Percy…” Annabeth took in a shaky breath, “Percy was the hero, and my knife was the blade. The _single choice_ –”

“Me,” Thalia said, “Me killing Luke.”

“...Right.” Annabeth muttered. “And the last line– _Olympus to preserve or raze._ It… it hasn’t happened yet, but the gods are down a member, we don’t have any children of the Big Three on our side, people are deserting left and right–”

“Wait,” Thalia interrupted. “What about Nico? He’s the son of Hades. Isn’t he…?”

Annabeth shook her head. “He helped us get out of the Labyrinth, when Clarisse, Grover, and I discovered that Kronos had possessed Thalia, but then he vanished again.”

“Where?”

“The Underworld,” Annabeth said, “to get information on the Curse of Achilles, and to find Beryl Grace.”

Thalia sucked in a breath. “This probably isn’t going somewhere good.”

“Nope,” Annabeth agreed. “Apparently, while our backs were turned, Thalia got to him. She promised that she could get Nico his sister back, along with her brother. Jason.” She looked Thalia squarely in the eye. “Sound familiar?”

Thalia closed her eyes. “My little brother,” she said hoarsely. “My mother had a hand in his death. Before all of this happened, I… I wanted to use this chance to resurrect him. I’d do anything for him.”

Annabeth smiled grimly. “Yeah, apparently, so would our Thalia. Nico wanted his older sister back, Thalia wanted her little brother back, and they decided to work together to… achieve that.”

Thalia cleared her throat. “In my world, Nico was able to get closure for Bianca. Did… did that not happen here?”

Annabeth shook her head. “He could never conjure her.”

“Oh.”

“So now, Thalia and Nico are on the same side, Thalia is the vessel of Kronos, she’s effectively invulnerable, the gods are in hiding, and we are holed up in a summer camp, waiting for the boundary to give out.” Annabeth shrugged. “At this point, it’s only a matter of time before they start a siege and raze Olympus to the ground.”

“So you’re just giving up?” Thalia asked.

Annabeth looked at her, and Thalia read the exhaustion in her face. “What else can we do?”

“I’m here now,” Thalia said. “I can help you.”

Annabeth let out a mirthless chuckle. “No offense, Thalia, but I think you’ve done enough.”

Thalia went silent. “Good point,” she mumbled after a few seconds. “Ouch, though.”

“Wait,” Annabeth said, and her face was pained. “Thalia, you were my friend. I… if you can give me anything, anything at all, about why she might have gone to Kronos…”

Thalia hesitated. “I don’t know anything for sure,” she said gently. “But… I do have a few ideas. I know why _I_ might have gone over, at any rate, in my timeline.”

Annabeth perked up the smallest bit. “Let’s hear it.”

“One, Jason,” Thalia began. “He died because of the gods and their meddling. Specifically Hera, but let’s not get into that. Two, Luke. I, um, sort of shot him right in front of my other self. And, well, I can kind of see her resentment there. Plus, if my best friend died in front of me, and then I died, too, but apparently I was the only one deemed important enough to save… yeah. Three, I don’t think she liked that I time-traveled there to help the gods, and she _really_ didn’t like that I took it upon myself to help the gods by killing Luke. Four, she’s never had a good experience with a god before. I have Artemis, but she has nothing.” Thalia shrugged. “I don’t condone what she did, but I can see why.”

Annabeth was silent.

“Um,” Thalia said. “Can I… can I ask you a question?”

Anabeth shrugged. 

“Okay, well… why aren’t you mad at me?”

Annabeth’s eyes were fixed on her knife. She was running the tips of her fingers on the edge of the blade. “How do you mean?”

“Well– I ruined everything. You should be furious.”

“I am,” Annabeth said. “But you still have one chance left, and we’re going to figure out how you can use it to help us.” 

There was the sudden blowing of a conch shell in the distance, and Annabeth stood. “Dinner,” she said, and extended a hand to Thalia. “Let’s go.”


	5. The Third Chance

**Summary for the Chapter:**

> Thalia and Alt!Annabeth make a plan.

**Notes for the Chapter:**

> What the living fuck is an update schedule?

Dinner was a horribly awkward affair.

Somehow, Annabeth had gotten the word out that Thalia was from an alternate dimension (which was easier to explain than saying “This is Thalia, she’s a time traveler and also the sole reason everyone we love is dead”. It also did not result in Thalia being brutally ripped apart, which was definitely a plus), but the campers still gave her a wide berth. Thalia didn’t blame them.

On the other hand, it was a testament to how weird their lives all were that they accepted that a dimensional traveler was in their midst without question.

Reluctantly, Chiron had allowed Annabeth to sit with Thalia at the Zeus table, probably to keep an eye on her and to make sure Thalia wouldn’t snap and destroy the entire camp with a single bolt of well-aimed lightning.

That was fair.

Thalia would also be suspicious of herself if she was in Chiron’s shoes. Hooves. Whatever.

So she ate fast and left fast. Annabeth was right beside her the entire time.

They walked down to the beach, and the salty smell of the water made Thalia think of Percy. Her eyes stung.

Trying to save her friends had killed Percy. Annabeth and the other campers were exhausted and defeated, trapped inside the borders of the camp, waiting for them to fail. Waiting to die.

She had ruined everything.

“I’m going to fix this,” Thalia said, eyes fixed on the horizon. “You’re right, I have one chance left. You have a plan, right?” It was a rhetorical question more than anything else. Annabeth always had a plan.

Annabeth did not disappoint. “Of course I do.”

Thalia took a deep breath. She would use her last chance, and stop all of this from happening, making a better world.

And as for Jason… 

Thalia would always love her little brother. But Jason was not bigger than the fate of the world.

“Tell me,” Thalia said.

* * *

“Okay,” Annabeth said. “I have a few ideas.”

They were sitting in the Zeus cabin, and when Thalia had gone looking for her little nook, she was unsurprised to see it dusty and obviously never used.

“So, we can’t afford to gamble on this chance,” Annabeth began. “Which means we can't get fancy about it. We just have to try to put everything back the way it was before you time traveled in the first place.”

“How do I do that?” Thalia asked. “I can’t just go back and knock out my younger self before she kills Luke. She’d see me and fight back. I’m not good at listening to messengers from the future foretelling my own doom, apparently. And I can’t go back to stop myself from accepting it from Kairos, either. That timeline’s gone.”

Annabeth frowned, rubbing her chin. “Maybe not. You know quantum superposition?” She paused, saw the horrified look on Thalia’s face, and smiled a little. “Sorry. I’ll explain. Basically, it’s the solution to the Schrödinger's Cat thought puzzle. A cat, a vial of poison, and a radioactive source are all put into a sealed box. If radioactivity is detected, the vial breaks, and the poison kills the cat. You following?” 

Thalia hadn’t gone to school beyond the fourth grade, and she had never graduated from that, but she nodded. “I guess…”

“In the absolute simplest of terms–”

“Thanks.”

“–because of quantum mechanics, the cat is simultaneously alive and dead, but until we open the box to check, the cat is always going to be one or the other, because it can’t be both. Reality collapses into one possibility or the other.”

“ _That’s_ supposed to be simple?” 

“What I’m saying is– the cat is both alive and dead. So, maybe, you’re like that.”

“What? I’m not dead in _either_ timeline! Isn’t that the _problem_?”

“But you’re here. You’re here, and so is your double. Logically, you shouldn’t exist, or you shouldn’t remember your old timeline because it’s been rewritten. But you do. So it might exist, superimposed over this timeline. Just like you and my Thalia. There shouldn’t be two of you; it’s not possible. But here you are. That has to be a sign that this timeline is wrong, that it isn’t supposed to be this way.”

“So you’re saying I could get back and punch myself in the face before I shoot Luke? Provided I can, you know, take a highly alert semi-immortal demigod by surprise?”

“Maybe,” Annabeth breathed, “but– what if– what if you were be able to go _sideways_?”

“What?” Thalia had never felt more lost in her entire life.

Annabeth’s eyes were suddenly dancing with excitement. “What if that orb you have doesn’t work based on time travel?”

Thalia blinked. “Huh? Yeah, it does. It’s a time traveling blob. That’s what it’s for.”

“Yeah, but the god that gave it to you is the god of opportunities, right? Kairos. This thing doesn’t work like a Tardis or a Time Turner. So, theoretically, you don’t need to go back and knock out your younger self. All you have to do is go back to when it was presented to you– and when the _opportunity_ first came up.”

Thalia was beginning to grasp what Annabeth was saying. “So I can go back to Kairos on Olympus and tell him ‘No thanks, I’m good’?”

Annabeth shrugged. “Theoretically.” 

“What d’you mean?”

“Well, we won’t know until you do it.”

“Yippee,” Thalia said. “I love being the test subject of intense physics experiments where the outcome is likely to be death.”

Annabeth just looked at her, but Thalia read her thoughts in the disapproving tilt of her eyebrows, and it looked a lot like _And WHOSE fault is that?_

_Good point. Still._

“It’s just so weird,” Annabeth mused.

“What?”

Annabeth shrugged. “I just can’t figure out why Kairos would give you three opportunities to travel through time, when the gods actually stood a chance, but he’s not doing anything here, where the gods are losing.”

Thalia shrugged. “Maybe he saw what I did to Luke and figured he didn’t want to make everything worse.”

“Maybe,” Annabeth said, sounding unconvinced. “But still…”

“Gods can make mistakes,” Thalia said with a shrug. “You know that better than anyone.”

“Minor god,” Annabeth said, half to herself. “Hm. His name sounds a little familiar.”

“He was the son of Zeus,” Thalia offered. “He called me his little sister.”

Annabeth’s brows furrowed. “The son of Zeus, huh?”

Thalia shrugged again.

“Okay,” Annabeth said. Her lips quirked up slightly. “Don’t take this the wrong way, but I hope I never see you again.”

Thalia laughed. “Fair enough,” she said.

“So, go back to the throne room and refuse the offer.” Annabeth said. “That should end all of this.”

“Okay,” Thalia said.

Annabeth hesitated a moment, then lunged forwards and hugged Thalia tightly. Thalia froze.

“Thank you,” Annabeth breathed into her ear.

Tentatively, Thalia hugged her back.

Annabeth was the first to pull back, her eyes suspiciously wet. 

Thalia called the orb into her palm and whispered, “August 17, 2009,” picturing the hall outside the throne room.

The last thing she saw was Annabeth’s gray eyes suddenly going wide and shouting, “Wait, Thalia, Kairos was–”

And then everything went black.

**Notes for the Chapter:**

> I would like to publically apologize for the cringey references to _Doctor Who_ and _Harry Potter_ , but I thought referencing a DeLorean would be one _Back to the Future_ reference too many, and my first choice for a reference was _Dark_ , which is honestly one of the best time travel shows on Netflix, but nobody watches it because it's in German (but it's still amazing! I don't speak a word of German and I loved it!). I also thought that those two were more recognizable time travel references than, say, a phone booth ( _Bill and Ted's Excellent Adventure_ ) or Time Safari Inc. ( _A Sound of Thunder_ )
> 
> Anyway, how are y'all doing today? I'm on day 155 in quarantine, so ao3 is currently saving my sanity.
> 
> Tell me what you think!


	6. The Opportunity (Redux)

**Summary for the Chapter:**

> Thalia arrives back on Mount Olympus, just in time for Kairos's arrival...

_**August 17, 2009** _

Thalia crashed to the floor, swearing loudly. Her leg– the one Kairos had temporarily healed– hit the floor first and she cried out in agony as pain raced up the limb.

Just a few more seconds. A few more _seconds!_

Oh, the irony of being a time traveler.

_Kairos was–_

_Kairos was–_

_Kairos was–_

Kairos was _what_?

Her thoughts were interrupted by a very loud and violent _“What the actual Hades?”_

Thalia opened her eyes. 

Her younger self, from only a few days ago, was staring at her from across the room, pinned beneath the statue.

_Oh, great. Here we go again._

She spoke quickly, before her younger self could do something stupid like murder her. “I’m not here to kill you, I _am_ you, I’m from a few days in the future, sort of–” What else could she say to remain non-electrocuted? “and Kronos didn’t send me, and we need to talk. Oh. Also, I’m a time traveler.”

Her younger self gaped at her. She was breathing hard from her position beneath the statue. “Time… travel,” she said. “ _Di Immortales_. Okay. Okay. Why… are you here?”

 _Well, that was easy_.

“Well,” Thalia said, and paused. Lying would probably be a very bad idea, given what had happened last time, and she was out of chances. She would have to tell the truth. “Actually, I’m here because in a few minutes, a god named Kairos is going to show up and offer you a chance to travel through time. You’ll get three chances.” Thalia’s leg was beginning to throb. “I took that offer, but…”

_Kairos was–_

Thalia shook her head, ignoring the pain in her thigh. “I messed it up. I went back in time to kill Luke.”

Her past self shot up– well, as much as she _could_ shoot up, anyway. Her breathing was still labored. “Luke? You killed… him?” she said. “That… might work. How… did it go?”

“I’m here warning you not to do it. How do you _think_ it went?”

Her younger self frowned. “I’d… do it differently,” she proposed. “I’d… fix your mistake. Whatever… it was. We could… still win. Without losing anyone.”

Thalia shook her head. “No. The mistake _was_ killing Luke. We can’t do that. I killed Luke, and then I accidentally pushed myself onto his path instead. We became Kronos. Camp Half-Blood was…” she thought of the campers’ empty eyes and the hopelessness in Annabeth’s voice, and shuddered. “It wasn’t good. We don’t have time for trial and error. We just have to keep the timeline the way it was meant to be.” 

“But… our friends,” her past self said. “Annabeth– Grover– Percy–”

“Not worth it,” Thalia said. “They’re still in the throne room. The gods are on their way. Their fight isn’t over yet. They can still survive. And… I don’t think I can go in there and help. My leg…” she tried putting weight on it and tried to bite back a hiss of pain. “Yeah, I’d be more of a hindrance than a help. We can’t interfere in the timeline.”

“So what… should we do?”

“You’re a lot easier to work with than the other one,” Thalia muttered. “Look, you can’t take the deal. The repercussions… they’re bad. We don’t know what the consequences are if we change something in the past. We can’t risk it.”

“What… about Jason?”

Thalia took a moment to take a deep breath. “We don’t know what will happen to him if we save him,” she said. “He could grow up and be happy. Or our mother could get rid of him a week later. Or he could be the new Luke. We… we can’t– we _shouldn’t_ – save him.” When her younger self looked ready to protest, Thalia quickly went on. “Come on, I’m _you_. If anyone wants to save Jason, it would be me. Please.”

Her younger self nodded reluctantly. “Okay.”

“Good,” Thalia said. “So. Don’t take the deal. Just say no, and hope reinforcements come. I know you don’t want to– Hades, _I_ don’t want to– but you have to.”

Her past self’s eyes glinted wetly. “I guess… you would know. Fine.”

Thalia picked up a piece of gilded wood that must have been a bannister at some point, and leaned on it as a makeshift cane. “Okay. I will… be over here.” She shuffled behind a half-destroyed column. “Remember not to take the deal. We have no idea what it could do to the timeline.”

“Yeah, I… got it.” her younger self wheezed. “Stay… hidden.”

Thalia flopped down on the floor behind the column and checked on her leg. Yep, it was definitely broken again. Hopefully this would all be over soon and she could get some nectar and ambrosia. It had been a very, _very_ long day.

Suddenly, there was a tiny _pop_ and Thalia tensed. That had to be him.

“Hello, little sister,” Thalia heard Kairos say.

_Here goes nothing._

“Who… are you?” she heard her younger self say, feigning ignorance. “You… a god? You here… to help?”

“That depends on you. My name is Kairos,” Kairos said. “I am here to offer you an opportunity, Thalia Grace.”

“Don’t… call me… that. What… opportunity?”

“Time travel,” the god replied. “I will give you three chances.” There was a pause, and Thalia heard her younger self gasp. “Using this orb, you can go to whatever time you like.”

“Could I… kill Luke?”

 _What?_ She was supposed to be rejecting it! 

“If you like,” Kairos said. “That seems like a quick way to win this war, doesn’t it?”

“It… does,” her younger self murmured.

“You should do that,” Kairos pressed. “To save Olympus. Getting rid of Kronos’s vessel, years before he comes to power.”

“What… about… my brother?”

Kairos hesitated. Thalia peered around the column to see him looking bemused. “I suppose,” he said, “but killing Mr. Castellan might bring a quick and painless end to the war, don’t you agree?”

“Yeah,” her younger self said. “But my brother…”

The god hesitated. “I will give you the orb,” he said reluctantly. “I suppose it is yours to do with what you wish.”

“Okay,” her younger self said, and Thalia felt her heart skip a beat.

“Wait!” she blurted out before she could stop herself, and scrambled out from behind the pillar, ignoring the god’s exclamation. “What the hell? We had an agreement!”

Her younger self met her gaze steadily. “I have… to save Jason,” she said. “Killing Luke… might be out, but saving… my brother… isn’t.”

“I swear,” Thalia growled, “If a future me ever drops out of the heavens and tells me to listen up, I’LL DO IT! Just to spite _you!_ ”

Her younger self shrugged. 

“Ugh!”

“Who are you?” Kairos snarled, shoving past Thalia’s younger self, who, Thalia realized belatedly, was still pinned beneath the statue.

“I’m Thalia,” Thalia said. “From a timeline where I killed Luke.” She lifted her spear, clutching her bannister-cane. “It didn’t go well. In fact, it went terribly. So, Mr. God-of-Opportunity. Why were you encouraging her to do that?”

_Kairos was–_

_Kairos was–_

Why couldn’t she have stayed for _two more seconds?_

Kairos was glaring at her now, still on tiptoe and still sporting that ugly, godsforsaken haircut. 

“You’re not lying,” he said silkily. “Hello, little sister.”

Thalia clutched her spear harder. She felt drained. She didn’t know if she could summon lightning. But she could bluff. “What are you doing?” she snapped. “You have to know that that won’t end well. Kronos will just find another vessel. Why would you… why would you…” she trailed off.

_Kairos was–_

Suddenly, everything made sense. Thalia reeled away from Kairos, stunned.

“You knew I would go kill Luke,” she said numbly. “You knew. You couldn’t have _not_ known. You’re the god of opportunities. You had to have known what I would do with mine. So that means… you…”

Kairos was glaring at her, eyes alight with hatred, as she put the pieces together.

“You’re working for Kronos,” Thalia said, horrified. “You’ve been on his side this whole time.”

It made a horrible amount of sense. Kairos was a minor god, and there were almost no minor gods on the side of Olympus. Plus, Kronos would have made sure no Olympian allies could get up here to help Percy. Kairos had tried to convince Thalia’s past self to kill Luke. Why? He had to know that Thalia would overlook the obvious, would forget that killing the vessel did not equate to killing Kronos forever. He had to know exactly what would push Thalia over the edge.

“You weren’t supposed to come _back_ ,” Kairos snapped, voice full of loathing. “How did you do it?”

“Annabeth,” Thalia said triumphantly. “Uh– don’t ask me about the specifics, though. Something about being dead and alive at the same time, and going sideways.”

Kairos growled. He did not seem as impressed by Annabeth’s intellect as Thalia was. 

“I was meant to overthrow Zeus when I was young,” he snarled, “as Zeus once overthrew _his_ father. But I was a coward, and I married Tyche instead. And what thanks did I get, for sparing the king of Olympus? I am a minor god. I have no worshippers. Zeus reaps the benefits of my inaction every day. And now, Kronos has given me a second chance. We must restore the natural order of things. Down with Olympus!”

He raised a fist before seeming to realize that neither Thalia was going to indulge him by agreeing with that. He lowered his arm sheepishly.

“I was tasked with distracting you from entering the throne room,” Kairos admitted, “either through fighting or talking. But then I realized you were trapped, and hurt, and so another idea came to me. If I could trick a child of the Big Three into working for Kronos, into trapping herself in an alternate world…” he shrugged. “I could become Kronos’s right hand. I could have more power than I’ve had in centuries!” He glared poisonously at Thalia. “But you… you’ve ruined all of that.”

“You’ve lost,” Thalia said simply. “You didn’t account for Annabeth Chase.”

“No, I did,” he said. “I just didn’t realize you would listen to her.”

“What? Why not?”

Kairos gestured at Thalia’s past self, who was clutching the orb and watching the two of them in horrified fascination. “You don’t even listen to yourself, little sister. How was I supposed to know you would take the word of the _alternate version_ of a teenage girl?”

“You know, that might be the first good point you’ve made to me so far,” Thalia said.

Kairos sat down on a ruined dais, evidently seeing no threat in either Thalia, which was fair. One was incapable of moving and the other was incapable of standing up on her own.

“My grandfather has already lost, little sister. He has missed his chance, and the prophecy will prove him wrong. But if I could change the timeline, erase this world and replace it with one where we prevail… now that was an opportunity I simply could not pass up.”

“He’s… _lost?_ ” Thalia’s younger self blurted out. “How did… that happen?”

“He will lose,” Kairos said, “Luke Castellan is gathering his strength. He is simply waiting for an opportunity to strike.”

“ _Luke?_ ”

“ _Luke?_ ”

Both Thalias spoke at the same time, creating an eerie effect as the same voice echoed twice.

Kairos scowled. “Yes.”

“You really can’t win, then,” Thalia said, and, unexpectedly, Kairos cackled.

“Of course we can’t win right _now_ ,” Kairos said sinisterly. “But what neither of you seem to realize is, now that I am aware of your use of it, _I_ can control where and when you land with that orb. I don’t need your consent.” He turned to grin at Thalia. “Didn’t you wonder why you happened upon your little gang of demigods so easily?”

Thalia could feel time slowing down as Kairos turned towards her younger self. She wasn’t sure if it was Kronos in the other room doing it, or her own, panic-riddled, ADHD brain.

Either way, she was moving too slowly as Kairos reached for the black orb.

“You might not feel inclined to kill Castellan anymore, but I can still make sure you throw the timeline into such disarray it will never recover!” he snarled. “What would happen if Thalia Grace appeared in the Labyrinth? It would look very suspicious– or what would happen if a second Thalia Grace took Bianca DiAngelo’s place in the land without rain? Or Zoë Nightshade’s? What if your sudden appearance distracted Percy Jackson or Annabeth Chase at a crucial moment?”

“No!” Thalia heard herself shout, and it took a second for her to realize that it was her younger self who had spoken. She was bent at an awkward angle, arm held out, playing a lopsided game of keep-away with Kairos. But Kairos was laughing, smirking, not even trying to get to the orb. His opponent was pinned. He was a god. He could take his time.

“Hey!” Thalia shouted. “Get away from her!”

Kairos turned to her, grinning, and Thalia realized that lightning was crackling around her.

Kairos wasn’t grinning anymore.

“Back off,” Thalia growled, and tossed her makeshift cane and her spear away, preparing to run.

“What are you doing, little sister?” Kairos demanded, and Thalia smiled at him.

“Seizing my opportunity.”

She dashed forwards, and Kairos leapt out of the way, but Thalia wasn’t aiming for Kairos.

Thalia slammed into her younger self with all the force of a determined demigod with nothing to lose except the entire timeline.

The orb skittered away as her younger self shrieked in pain.

“NO!” Kairos roared.

Thalia dove for the ball.

Her hand closed around it.

And then Thalia was flying backwards, propelled by a blast of energy. She hit the wall and had about two seconds to think _whoops, I probably shouldn’t have done that_ before Kairos vanished in a blinding flash.

Everything went white.

**Notes for the Chapter:**

> told you you should keep an eye on kairos :)  
> anyway just a quick epilogue left and then we're done! thank you to everyone who read this story. tell me what you think in the comments! ❤️


	7. The Future

**Summary for the Chapter:**

> Thalia wakes up, and the war is over.

**Notes for the Chapter:**

> Posting this at midnight, so hopefully there aren't many typos

_**August 18, 2009**_

Thalia woke up exhausted, which sort of defeated the entire purpose of going to sleep in the first place.

There were half-bloods and Hunters and Olympian allies milling around, and it took a few seconds for Thalia to realize she was still on Olympus.

Slowly, she propped herself up on her elbows and looked around.

She was one of what looked like hundreds of injured half-bloods, all lying on the ground in neat rows as satyrs and healers picked their way around them. Thalia herself was lying on a folded blanket, which seemed to be serving as a makeshift cot. Her leg was covered in bandages, which were glowing faintly. Her head and back were aching fiercely, but it wasn’t as bad as Thalia would have expected, after being thrown into a wall.

_Apollo_ , Thalia thought. Either him, or one of his children. The leg was feeling better already. 

“You’re awake!”

Thalia tilted her head to see Mari, a tiny Hunter who was a daughter of Apollo, making her way towards her. The relief on Mari’s face was palpable as she crouched beside Thalia and helped her sit up.

“Who’s still alive?” Thalia demanded, heart in her throat. If her friends had died, after everything they had gone through, after everything Kairos had done… 

But Mari smiled, and ticked off her fingers, biting her lip as she thought.

Annabeth had survived. Percy had survived. Grover had survived.

There was some hesitation.

“What?” Thalia said.

“Um,” Mari said, fidgeting uncomfortably. “Well. Luke Castellan died.”

Thalia closed her eyes.

“Okay,” she whispered. “Okay. Thank you.”

“Yeah,” Mari said softly. “You’re welcome. I… I know you were friends.”

“No, we weren’t,” Thalia said roughly. She could feel her lips twitch. “If I had the chance, I would have killed him myself.”

Mari blinked at her in surprise, and they sat in silence for a few seconds.

“What happened to me?” Thalia croaked finally. “Who brought me here?”

“Oh! The Cyclopses did. They had to save your life,” Mari said, eyes wide. “You were unconscious underneath that statue of Hera. You were barely breathing.”

“What?” Thalia said. “But I wasn’t under the statue, I got thrown into a wall.”

Mari frowned. “No,” she said slowly, “you were definitely _under_ the statue. Maybe it fell on you after you lost consciousness.”

“I was on the other side of the room!” Thalia snapped, irritated. She could feel her headache getting worse. “Look, was there anybody else in there?” _Liiiiiike a completely identical version of me, for example? Or a god with a terrible haircut?_

“No,” Mari said, looking bemused. “Why?”

_Well, that’s not good. What could Kairos be doing with the orb– and my other self?_

“I was fighting someone,” Thalia said quickly. “A minor god, named Kairos. He had this orb… actually, it’s a bit of a long story. I’ll tell you later.”

“Kairos,” Mari muttered to herself. “Doesn’t sound familiar.”

“Yeah, I think that was the problem in the first place.”

Mari shrugged. “Well, I can tell Lady Artemis to keep a sharp eye out. And let Lord Zeus know about this so he knows that Kairos betrayed Olympus.”

“Thanks, Mari.”

The little Hunter brightened. “No problem!”

Thalia nodded at the bandages on her leg. “So… when do these come off?”

“Oh,” Mari looked at the leg, shuffling over to look at it more closely. “Hm. Maybe a week?”

Thalia felt her mouth open in dismay. “A _week_?”

Mari looked faintly amused. “You’ve been given nectar, ambrosia, and healing by the most skilled of Apollo’s children. It was a nasty break. For mortals, healing it might take months. It’s only a week. It’s not that long of a wait.”

“Yeah, well, I hate waiting,” Thalia grumbled sourly, and Mari laughed.

* * *

The gods put on a whole ceremony as a thank-you-Percy-for-saving-us-from-total-annihilation party, but Thalia was both a little dazed from her whole ordeal with Kairos and a bit high on the taste of nectar, and was therefore too out of it to really register what was going on. Zeus had thanked her. Artemis had promised her help. Thalia had gone through the motions robotically, too tired to think.

Afterwards, though, the first thing she did was find Percy and hug him.

The second thing she did was find Luke’s body. It looked so small. And she knew now how easily that that body could have been hers instead.

She didn’t feel pity. Luke made his choice. And in another world, in another time, she would have made that choice, too. So, no. She felt no pity. But she did feel sorrow.

Thalia allowed herself a moment to sit by the body, to remember Luke, the way she knew him, when he was fourteen and brash and protective and wonderful. 

As she stood to leave, though, she made the three-clawed gesture over her heart. And then she walked out.

She let the door close behind her, and the echoing _thud_ had an eerie sense of finality to it.

When Artemis asked her, later, if she was okay, Thalia just smiled, a little sadly, and gave an affirmative as she surveyed the Hunters making camp, not far from where Luke Castellan had died in another lifetime. 

It was scary to know what she could have been capable of. It was scary to know that, once upon a time, Thalia herself could have been the child of the prophecy and Kronos’ puppet simultaneously. She had only escaped this cruel trick of fate through sheer luck.

But as Thalia watched the sun set, she took a deep breath and let it out. She was a Hunter. She was the daughter of Zeus. Kronos was gone. Luke was dead. They had won.

Her younger–other?– self and Kairos were still missing. But for now, everything was still and silent. Her Hunters were safe. Her friends were safe. And Thalia was tired.

For now, she would just have to watch the woods around her carefully, and wait for opportunity to knock.

**Notes for the Chapter:**

> Aaand it's done!
> 
> I can write a sequel if y'all are interested, but if not, I think I'll just leave it open-ended. Thank you to everyone who read this! ❤️
> 
> Tell me what you thought!


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